Cardiac electrode means



n. G. KILPATRICK 3,087,486

CARDIAC ELECTRODE MEANS April 30, 1963 Filed March 5, 1959 FGl JNVENTQR.

DAVID G. KILHTRICK ym @MM ATTORNEY FlCll 3,087,486 Patented Apr. 30, 1963 3,087,486 CARDIAC ELECTRODE MEANS David G. Kilpatrick, East Norriton, Pa., assignor, by mesne assignments, to Ceiico Instruments Corporation, Chicago, Ill., a corporation of Delaware Filed Mar. 5, 1959, Ser. No. '797,372 13 Claims. (Cl. 12S- 2.1)

This invention relates to surgical apparatus and, more particularly, to a probe for making electrical contact with the myocardium to monitor or articially stimulate the heart.

While various types of electrodes have been proposed for making electrical contact with the heart, such have not been entirely satisfactory. ln order to make proper electrical contact with the myocardium, the electrode must have suicient rigidity to penetrate the chest wall and to be moved into proximity with the heart. On the other hand, such electrode should be suilicientiy llexible to allow the free movement of the heart and to maintain electrical Contact therewith and Without damaging same. Any electrode embedded in the heart and extending outwardly through the chest wall that lacks the ability to freely move with the heart, can fatally damage the myocardium or become disengaged theretlrorn. It is therefore an object of the present invention to provide a cardiac electrode assembly that is extremely simple in construction, extremely effective` and which will overcome the aforementioned diiliculties.

Another object of the present invention is to provide a substantially self-contained cardiac electrode assembly which will sequentially penetrate the chest wall and malte electrical contact with the myocardium without multiple incisions, and in a relatively short period of time.

Still another object of the present invention is to provide a cardiac electrode assembly of the type described that will effectively carry an extremely flexible conductor into contact with the myocardium, following which certain elements thereof `may be removed leaving the electrical conductor in contact with the heart for very long periods of time if necessary.

Still another object of the present invention is to provide a cardiac electrode assembly of the above type having self contained means for first penetrating the chest wall and then driving an extremely `flexible electrical conductor tinto the myocardium for continuous contact therewith, following which all parts of the assembly except the conductor may be removed from the chest wall to provide maximum comfort to the patient and continued stimulation of the heart by an artificial pacemaker.

All of the foregoing and still further objects and advantages of this invention will become apparent from a study of the folowing specication, taken in connection with the accompanying drawingwherein:

FIGURE l is a longitudinal cross sectional view of the cardiac electrode assembly made in accordance with one form of the present invention with the parts in an initial position immediately prior to penetrating the chest wall;

FIGURE 2 is an enlarged fragmentary longitudinal cross sectional view of certain parts of the assembly shown in FIGURE l. showing the details of construction thereof;

FIGURE 3 is a diagramatie view illustrating the actual use of the cardiac electrode assembly shown in FIG- URE l, in an initial position following penetration of the chest wall;

FIGURE 4 is a view similar to FIGURE 3, showing an adjusted position of the parts in which the electrical contact is driven toward the myocardium;

FIGURE 5 is a view similar' to FIGURE 4, showing the contact embedded in the myocardium and other parts of the unit being withdrawn from the chest wall;

FIGURE 6 is a View similar to FIGURE 5, showing al1 of the cardiac electrode assembly, except for the electrical conductor, removed from the chest wall;

FIGURE 7 is an enlarged side elevational view, with parts broken away, of a slightly modified form of cardiac electrode assembly, with the parts in an initial position;

FIGURE 8 is a view similar to FIGURE 7, showing the electrical conductor in an extended position;

FIGURE 9 is an enlarged fragmentary longitudinal cross sectional view taken along line 9-9 of FIGURE 8;

FIGURE 10 is a side elevational view, with parts broken away, of still another embodiment of the present invention with the electrical conductor in an extended position; and

FIGURE ll is an enlarged fragmentary longitudinal cross sectional view taken along line 11-11 of FIG- URE l0, showing certain details of construction.

Referring now more in detail to the drawing, and more particularly to FIGURES l through 6 thereof, a cardiac electrode assembly 20 made in accordance with one form of the present invention is shown to include a tubular carrier sleeve 22 which resembles a conventional hypodermic needle, having an oblique point 23 at one end and an enlarged head 24 at the opposite end. This carrier sleeve 22 is sufficiently rigid to penetrate a human chest wall and is long enough to provide full penetration into the chest cavity without engaging the heart.

An elongated plunger sleeve 27 is slidably received within the longitudinal bore 25 of the sleeve 22, which plunger 27 is also provided with a longitudinal bore 28 through which an electrode 32 slidably extends. The outer end of the plunger 27 is provided with an enlarged pressure plate 30 which may be used to move the plunger 27 toward the pointed end 23 of the sleeve. The electrodc 32 is flexible throughout its entire length, while the innermost end thereof is provided with a point 34 for piercing the myocardium, as will be hereinafter more fully described. A stop element 36 in the form of a collar having a forwardly facing abutment surface 3S and a rearwardly tapered surface 37 is fixed upon the electrode 32 adjacent to the point 34. This stop is provided for the purpose of limiting penetration of the myocardium by the point 34, which functions as a contact for the electrode 32 and which must come to rest within a predetermined layer of the heart wall to provide proper monitoring or stimulation thereof. Except for the point 34, the entire electrode 32 and stop 36 are coated with a dielectric material 33 which electrically insulates all but the point of the electrode from the rest of the assembly and from body tissue and uid. This insulation prevents `shorting of the electrode at any point between the opposite ends thereof while passing through the body tissue or sleeve 22 which tissue and sleeve 22 provide a return path through an associated lead 44 electrically connected thereto.

In actual use, the parts of the cardiac electrode assembly 20 are initially positioned in the manner shown in FIGURE l with the contact point 34 of the electrode retracted into the interior of the sleeve 22. The carrier sleeve 22 may then be used to pierce the chest wall 46, protecting the tiexible electrode 32 temporarily encased within the interior thereof. As soon as penetration has been made, the pressure plate 30 and plunger 27 are depressed, so that the inner end of the plunger acts against the stop 36 which is fixed to the electrode 32 to drive the contact point 34 thereof outwardly through the pointed end 23 of the sleeve 22 and toward the myocardium 42, as shown in FIGURE 4. Slight additional pressure is required to drive the contact point 34 into the myocardium, as shown in FIGURE 5, following which the plunger 27 is withdrawn into the interior of the sleeve 22. Electrical connections may then be made to electrically connect the end of the electrode 32 opposite the contact point 34, to the artificial electrical pacemaker apparatus, the associated return lead 44 providing a return circuit through the conductive sleeve 22 and the body tissue. An axial pressure of approximately two ounces may be exerted upon the electrode 32, thus providing a slight bow 32', which will enable the flexible electrode to follow the motion of the heart, while also providing suficient slack to prevent the movement of the heart from working the contact point 34 out of the myocardium. This allows stimulation of the heart by an artificial pacemaker for very long periods of time.

If desired, all but the electrode 32 may be removed from the chest wall 40, in the manner shown in FIGURE 6, in which case the return circuit through the body tissue may be through an independent conductor 46 which may be inserted beneath the skin and secured therein by sutures 45. With this arrangement, only the flexible electrode 32 and return lead 46 will extend outwardly from the chest of the patient, for monitoring or articial stimulation of the heart for longer periods of time and for improving the patients comfort.

The rearwardly tapered surface 37 of the fixed stop 36 facilitates the withdrawal of the electrode through the chest cavity and chest wall of the patient when artificial stimulation of the heart is to be discontinued. If necessary, the electrode 32 may be threaded through the sleeve 22, so as to enable the sleeve to penetrate the chest wall again for the purpose of retracting the stop 36 and contact point 34 into the interior thereof, thus facilitating the withdrawal of the Stop and contact point outwardly through the chest wall.

Referring now to FIGURES 7 to 9 of the drawing, a modified form of construction 50 is shown wherein the tubular carrier sleeve 52, having a central longitudinal bore 53, is provided with a head 54 at one end and a plurality of circumferentially spaced apart slits 55 that are adjacent to and open outwardly of the opposite end. These slits 55 define a plurality of flexible segmental fingers 56 which are formed to converge toward their free ends to define a chest wall penetrating point 57. These fingers S6 are also preferably bowed outwardly to define an interior compartment or housing 59, within which a contact point 65 and fixed stop collar 60 of a fiexiblc electrode 61 are housed in an initial position. The entire electrode 61, except for the electrical contact point 65, is insulated with a layer of dielectric material 66, such as epoxy resin, for purposes hereinbefore described. A return lead 58 which is electrically connected to the conductive carrier sleeve 52 provides a return through the body tissue.

With the parts of the assembly 50 shown in FIGURES 7 to 9 in the position particularly illustrated in FIGURE 7, the slotted point 57 of the relatively rigid carrier sleeve 52 is used to pierce the chest wall, following which the electrode 61 is moved inwardly `toward the heart. Such inward pressure upon the electrode causes the Contact point 65 and the rearwardly tapered sto-p collar 60 to spread the flexible fingers 56 apart sufficiently to .allow the contact point 65 to penetrate the myocardium, m the manner shown in FIGURE 8. Once this penetration has been made, the electrode 61 and lead 58 may be electrically connected to the pacemaker apparatus, or the sleeve 52 may be withdrawn from the chest wall, leaving the contact point 65 embedded in the myocardium, and using a sutured electrode for providing a return through the body in the manner hereinbefore described.

Reference is now made to FIGURES and 11 of the drawing, which illustrate still another form of cardiac electrode assembly made in accordance with the present invention. This assembly 70 includes a substantially rigid carrier sleeve 72, having a longitudinal bore 73, with a head 74 at one end, and a chest wall piercing point 75 at the opposite end. A tiexible electrode 76 slidably supd ported within the longitudinal bore 73 has a contact point 77 at one end which is initially retracted into the interior of the carrier sleeve. Except for the contact point 77, the rest of the electrode 76 is completely encased within `a dielectric layer 78 of any suitable material. A return lead 71 connected to the head 74 provides a return circuit through the `body tissue, in the manner hereinbefore explained. This assembly is used in the manner hereinbefore described. With the contact point 77 in an initial retracted position within the carrier sleeve 72, the carrier sleeve is used to penetrate the chcst wall and to bring the contact point 77 safely into the chest cavity, following which the electrode 76 is moved toward the heart and the contact point 77 driven to a `predetermined depth into the myocardium to ensure proper electrical contact for monitoring or stimulating the desired layer of the heart iwall. The opposite end ofthe electrode 76 and the return lead 71 may then be connected to the pacemaker apparatus, or the carrier sleeve 72 may be drawn from the chest wall and the lead 71 replaced by the sutured electrode, in the manner hereinbefore explained.

It `will now be recognized that a cardiac electrode assembly has been provided in accordance with the present invention, for effectively introducing one end of an electrode that is flexible along its length to the myocardium, directly through the chest wall. While the degree of ilexibility of the electrode may vary, the carrier sleeve in all cases serves to carry the pointed electrical pointed contact into the chest cavity, from which it can be readily moved into contact `with the heart. Suitable measuring or sensing `apparatus may also be used to determine the proper depth of penetration of the contact point of the electrode. In the embodiment illustrated in FIGURES l through 6 of the drawing, the movement of the contact point 34 into the myocardium is more positively effected by means of the plunger sleeve 27 which also prevents kinking of the flexible wire within the chest cavity and provides `better guidance for the remote contact point 34 in the vicinity of the heart.

While this invention has `been `described with particular reference to the construction shown in the drawing, it is to be understood that such is not to be construed as imparting limitations upon the invention, 'which is `best defined by the claims appended hereto.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

l. A medical instrument comprising a rigid sleeve and an extremely flexible electrical connductor longitudinally slidable through said sleeve, said conductor having an end portion protruding from one end of said sleeve and restrained from retracting into said sleeve, said protruding end portion terminating `in a point and being provided with a shoulder whose diameter is greater than the inside diameter of said sleeve.

2. The instrument of claim l characterized in that said sleeve is electrically conductive and in that the outer surface of the portion of said conductor which is retractable into said sleeve is electrically insulated.

3. A medical instrument comprising a rigid sleeve and an extremely flexible electrical conductor longitudinally slidable through said sleeve, said conductor having an end portion protruding from one end of said sleeve, said protruding end portion terminating in a pointed configuration and having a protrusion extending laterally from said end portion far enough to prevent said end portion from retracting into said sleeve.

4. A medical instrument comprising a rigid sleeve, and a flexible conductor extending longitudinally through said sleeve, said conductor having one end portion protruding from said sleeve, said protruding end portion being provided `with a protrusion extending laterally from said end portion far enough to prevent said end portion from retracting into said sleeve, other portions of said conductor being freely slidable longitudinally through said sleeve, said sleeve being electrically conductive, and said conductor having a coating of electrical insulating material on all those portions lof said conductor which are slidable through said sleeve and having at least part of said protruding end portion free of said insulating coating.

5. A medical instrument comprising: a first rigid sleeve; an extremely exible electrical conductor extending longitudinally slidable through said sleeve, said conductor having one end portion protruding from one end of said sleeve, said protruding end portion being provided with a protrusion extending laterally from said end portion far enough to prevent said end portion from rctracting into said sleeve, other portions of said conductor being freely slidable longitudinally through said sleeve; and a second rigid sleeve longitudinally slidable over both said tirst sleeve und said protruding end portion of said conductor.

6. The instrument of claim 5 further characterized in that said second sleeve has a body-tissue penetrating contiguration at the end adjacent said protruding end portion of said conductor.

7. A cardiac electrode comprising, in combination, a flexible electrical conductor having a heart engaging electrical contact at one end, a carrier sleeve having a chest wall piercing point at one end and receiving said electrical Contact of said conductor within said one end for protected movement through a chest wall, said electrical contact being selectively movable independently of said carrier sleeve for following the movement of the heart, said conductor being slidably supported within said sleeve for selected longitudinal movement between an initially retracted position and an adjusted extended position for engaging said Contact with the heart independently of said sleeve after entry into the chest cavity, said conductor comprising a length of llexible wire, dielectric means electrically insulating said length of wire from said sleeve, said contact comprising a piercing point, and a xed stop secured upon said conductor adjacent to said point limiting the penetration of said point.

8. A cardiac electrode as set forth in claim 7, further comprising a plunger slidably enveloping said conductor, said plunger being slidahly supported within said sleeve, one end of said `plunger abutting said fixed stop and the other end of said plunger extending outwardly from said sleeve, whereby movement of said plunger in one direction against said stop imparts movement to said conductor relative to Said sleeve.

9. A cardiac electrode comprising, in combination, a ilexible conductor having a heart engaging electrical contact at one end, a sleeve slidably sup-porting said one end of said conductor for reciprocating longitudinal movement to selectively displace said contact between an inwardly retracted position and an outwardly extended position relative to one end of said sleeve, a chest wall piercing point at said one end of said sleeve, dielectric means electrically insulating said conductor from said sleeve, said heart engaging electrical Contact comprising an electrically conductive myocardium piercing point, and a stop xed upon said conductor adiacent to and electrically insulated from -said point limiting the penetration of said point into the myocardium.

10. A cardiac electrode as set forth in claim 9, wherein said one end of said sleeve slidahly accommodates longitudinal movement o said stop therethrough with said dispiacement of said contact.

1 1. A cardiac electrode as set forth in claim 10, wherein said sleeve includes a plurality of circumferentially spaced apart and longitudinaliy extending slits adjacent to and opening toward said one end thereof, said slits defining a plurality of circumferentially spaced apart segments, the free ends of said segments converging toward said one end of said sleeve .to define a substantially closed compartment enclosing said contact in said inwardly retracted position, and said segments being yieldable in a radially outward direction to accommodate movement of said point and stop of said conductor longitudinally outwardly of said compartment.

12. A cardiac electrode as set forth in claim 1t), further comprising a hollow plunger slidably supported within said sleeve, said conductor being slidably supported Within said plunger for longitudinal movement relative thereto, said contact point and said tixed stop projecting outwardly from one end of said plunger, said stop having one end facing said one end of said plunger, whereby longitudinal movement of said one end of said plunger within said sleeve into contact with said abutment means drives said Contact point outwardly of said sleeve.

13. A cardiac electrode as set forth in claim 12, wherein said stop comprises a collar secured to said conductor, and said one end of said collar is tapered in a direction toward said plunger.

References Cited in the file of this patent UNITED STATES PATENTS 1,913,595 Hyman et al lune `13, 1933 2,437,697 Kalom Mar. 16, 1948 2,637,316 Grez e May 5, 1953 2,729,211 Peter lan. 3, l1956 2,767,703 Nieburgs Oct. 23, 1956 2,839,049 MacLean June 17, 1958 2,955,591 MacLean Oct. 1l, 1960 2,955,592 MacLean Oct. 11, 1960 OTHER REFERENCES Guyton et al.: Article, American Journal of Physiology, volume 167, No. 1, Oct. 1, 1951, pp. 81-87. (Copy in Division 55.) 

1. A MEDICAL INSTRUMENT COMPRISING A RIGID SLEEVE AND AN EXTREMELY FLEXIBLE ELECTRICAL CONNDUCTOR LONGITUDINALLY SLIDABLE THROUGH SAID SLEEVE, SAID CONDUCTOR HAVING AN END PORTION PROTRUDING FROM ONE END OF SAID SLEEVE AND RESTRAINED FROM RETRACTING INTO SAID SLEEVE, SAID PROTRUDING END PORTION TERMINATING IN A POINT AND BEING PROVIDED 